- LR-I, HR-S, and HR-I: Patients receive vincristine IV on days 1, 8, 22, and 29; oral dexamethasone twice daily on days 1-14 and 22-35; cyclophosphamide IV over 30 minutes on days 43 and 57; cytarabine IV or IM on days 43-46 and 57-60; oral thioguanine on days 43-49 and 57-63; and methotrexate IT* on days 1, 22, and 43.